1. Field of the Invention
The present invention relates to an electrically driven wheelchair.
2. Description of Background Art
Electrically driven wheelchairs with manually rotated drive wheels with an assisted drive are well known. For example, electrically driven wheelchairs are disclosed in Japanese Laid Open Patent Application No. Sho-51-100556, and Japanese Laid Open Patent Application No. Hei-8-117291. These wheelchairs can be folded in two along their width for transportation and storage. Also, wheelchairs are known wherein the motor is housed within the hub of the drive wheel and when folding, the left and right wheels are separated from the motor and frame.
However, the above-mentioned models, wherein the drive wheels are separated, are divided into three construction parts. Of these parts, the wheelchair body frame contains electrical equipment including the battery which is both bulky and heavy. This separation when compared to the weight of the drive wheels is unbalanced due to the large difference in the weight distribution. Therefore, it is difficult for a user to load the heavy separated parts into a transportation vehicle, etc. Also, when assembling the wheelchair, as the drive wheel is first attached to the one side of the frame, after which, The remaining wheel is then attached to the other side, the wheelchair frame tends to become unbalanced, again making it difficult for a user to assemble the wheelchair.
In addition, a fold-up type wheelchair with an electrical driving apparatus attached thereto is provided with a saccate box containing a battery mounted to the back side of a cloth seat as disclosed in Japanese Laid Open Patent Application No. Hei-7-313555.
However, in the Japanese Laid Open Patent Application No. Hei-7-313555, the operation of removing the battery for changing, etc., is difficult since each time the saccate box must be detached from the seat. In addition, it is inconvenient as the saccate box can not be detached while remaining seated on the seat, making it impossible for this operation to be performed by the wheelchair user.
Furthermore, it is desirable to make it possible to use the wheelchair outdoors to support an active life-style. However, in general, wheelchairs with an electrical driving apparatus attached, including the wheelchairs disclosed in the related art are, on the whole, intended for indoor use. Therefore, it is necessary to give consideration to the protection of the electrical equipment from dirt and debris such as mud, flying stones and water, etc., when used out doors.